Luminescent sign



FIG. 1 is a perspective view of a luminescent sign shown in a first state in a sequence of illumination, showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a front view of the luminescent sign shown in a second state in the sequence of illumination; and,

FIG. 4 is a front view of the luminescent sign shown in a third state in the sequence of illumination.

The dashed broken lines depict portions of the luminescent sign which form no part of the claimed design. The groupings of three dashed lines represent illumination, and form no part of the claimed design. The process by and period over which one state of illumination transitions to another state of illumination forms no part of the claimed design. 

CLAIM The ornamental design for a luminescent sign, as shown and described. 